Battery Hold Downs

I'm setting up for a South America trip so 2 batteries on each side with solar and HD alternator connection and a 2kw inverter as to make the not very available hookups basically unnecessary. Cabling for 2kw needs to be 2/0 for 275 amp max so cabling and connections get to be a real issue. Basically I'll use an Anderson connector with fusing and manual shutoff for the batteries and a 100A lift gate plug for the alternator. I'll be using AGM batteries so I don't have to get too them and am planning on welding up steel angle frames to hold 2 batteries each with hold down brackets. Due to many rough back roads I really need them snugged down. I'll be doing the camper on/camper off game next week to try to figure out the connection and battery locations. Even the 300 amp fuse block is about 2"x2"x6" and where to put it so that it is accessable is an issue as if it blows and I can't get to it then I will need to manually jack the camper off the truck. Making all this work is an interesting project.

I really appreciate the input.